Synthesis of NHC Complexes with an N‐(2‐Oxopropyl) Group

Abstract

AbstractThe unsymmetrically N,N’‐substituted NHC precursor N‐(2‐oxopropyl),N’‐picolylbenzimidazolium chloride (H‐1)Cl, featuring an N‐protecting group has been prepared. Reaction of (H‐1)Cl with Ag2O followed by transmetallation of the NHC to [MCl2(Cp*)]2 (M=Rh, Ir) yielded complexes [MCl(Cp*)(κ2‐1)]Cl (M=Rh, [2]Cl; M=Ir, [3]Cl) with a chelating coordinated CNHC Npyridine ligand. Anion exchange gave complexes [2]BF4 (M=Rh) and [3]BF4 (M=Ir). Transmetallation of the NHC ligand from silver(I) to gold(I) gave the mononuclear complex [AuCl(1)] [4] bearing a monodentate, N‐picoly funtionalized NHC ligand. Complex [4] reacts with AgBF4 to yield the dinuclear complex [5](BF4)2 featuring two bridging μ2‐CNHC Npyridine ligands. The molecular structures of [2]BF4 ⋅ CH2Cl2 and [3]BF4 ⋅ CH2Cl2 have been determined by X‐ray diffraction studies.